Heavy-Duty Tire Tread Groove Layout for Wet Grip and Low Rolling Resistance
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Solution Overview
Problem
Heavy duty tires with lateral grooves for improved wet performance suffer from increased rolling resistance and reduced wear resistance due to low stiffness of land portions, which are exacerbated by groove wear.
Innovation Solution
A tire design featuring circumferential grooves and block-shaped land portions with shallower lateral grooves and irregular circumferential grooves with zigzag or wavy edges, where the edges serve as edge components to maintain stiffness and compensate for groove wear, enhancing wet performance while reducing rolling resistance and wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lateral grooves are provided on land portions to improve wet performance, then wet performance is improved, but rolling resistance increases and wear resistance decreases
Solution Approach 1:
The patent applies local quality by making the lateral grooves shallower in specific regions (shoulder land portions) compared to other areas, allowing wet performance improvement where needed while preserving land portion stiffness and reducing rolling resistance in critical areas. The groove depth is locally optimized rather than uniformly applied.
Solution Approach 2:
The patent changes the parameter of groove depth, specifying that lateral grooves in shoulder land portions have a depth of 0.4mm or less, which is shallower than in other regions. This parameter change allows the tire to maintain wet performance while preventing excessive stiffness reduction that would increase rolling resistance.
2Loss of energy
If lateral grooves are made shallow to suppress stiffness decrease, then rolling resistance and wear resistance are suppressed, but wet performance decreases due to groove disappearance
Solution Approach 1:
The patent applies local quality by differentiating groove depths in different regions: shoulder land portions have shallow grooves (0.4mm or less) to maintain stiffness, while other land portions have deeper grooves to ensure wet performance. This local differentiation allows both shallow groove benefits and adequate wet performance to coexist.
Solution Approach 2:
The patent segments the tread into different regions (shoulder land portions vs. other land portions) with different groove characteristics. This segmentation allows the tire to optimize wet performance and rolling resistance independently in different zones, with shallow grooves in shoulder areas and deeper grooves elsewhere.
3Reliability
If lateral grooves are deep to maintain wet performance, then wet performance is improved, but land portion stiffness decreases excessively
Solution Approach 1:
The patent applies local quality by restricting deep grooves to non-shoulder regions while maintaining shallow grooves in shoulder land portions. This allows the tire to concentrate stiffness-critical areas in the shoulder regions while permitting deeper grooves in central regions where stiffness requirements are lower, optimizing both wet performance and structural integrity.
Data Source
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AI summary
A heavy duty tire includes a tread (1) configured to come into contact with a road surface. The tread has a block-shaped land portion (12) having blocks (18) aligned in a circumferential direction and having a lateral groove (16) between adjacent blocks. Circumferential grooves (10) are located on both sides of the block-shaped land portion (12), and are each an irregular circumferential groove having a non-flat groove wall. The lateral groove (16) is shallower than the irregular circumferential groove (10). An opening of the irregular circumferential groove (10) includes a pair of edges (14) extending straight or in a zigzag or wavy manner. A virtual opening of the irregular circumferential groove (10) obtained by virtually cutting the tread along a plane including a groove bottom of the lateral groove (16) includes a pair of virtual edges (24) extending in a zigzag or wavy manner. An amplitude of each virtual edge (24) is larger than an amplitude of each edge(14), and a number of the virtual peaks included in the virtual edge (24) is larger than a number of the lateral grooves (16) included in the block-shaped land portion (12).